It is known in the prior art to provide a flow control device such as a piston in a conduit such that when coolant flows in a forward direction, the device engages and meters the flow of the coolant. When the piston is disengaged, flow of the coolant is reversed and flow is in an unrestricted manner.
When flow control devices are positioned within a conduit and are further positioned to move in a predetermined manner with respect thereto, flow conditions often result in high fluid velocities in the areas close to or adjacent to the device. Consequently, operational noise associated with the flow and turbulence of the fluid as it moves in relation to the device is thereby produced. Operational noises traditionally tend to be rattles, vibrations and the like. Additionally, the fundamentals of fluid mechanics teach that the forces developed by moving fluids result in noise and turbulent flow near the device. This is in part attributable to the unequal distribution of noise levels passing over the piston or flow control device.
Attempts to reduce noise level associated with flow control devices have been of limited success. For example, U.S. Pat. No. 4,896,696 to Bradley, et al discloses a flow control restrictor. However, there is still a need in the art for a flow control device which further reduces operational noise and eliminates other disadvantages associated with the prior art such as difficulties with respect to sizing, fit, sticking, cocking and failure to seat correctly.
It would therefore be desirable to provide a flow control device which controls the rate of flow in one direction, provides unrestricted flow in the reverse direction and which eliminates the shortcomings associated with the prior art.